A Deterministic Elastohydrodynamic Lubrication Model of High-Speed Rotorcraft Transmission Components

Cioc, Carmen; Cioc, Sorin; Moraru, Laurentiu; Kahraman, Ahmet; Keith, Theo G.

doi:10.1080/10402000208982587

Cited by 26 publications

(9 citation statements)

References 11 publications

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“…Distributions of the lubricant pressure and thickness across an elastic lubricated contact can be obtained by solving the transient Reynolds equation simultaneously with a number of other equations including the film thickness equation, the energy balance equation, viscosity-pressure-temperature relationship, density-pressure-temperature relationship, and the load equation [76]. In this study, an EHL model based on the model proposed by Cioc et al [76] will be used. Assuming that a hypoid gear pair exhibits nearline contact conditions, the dimensionless transient Reynolds equation is written as…”

Section: Calculation Of Friction Coefficient Using An Ehl Modelmentioning

confidence: 99%

“…The rolling velocity u is defined as u = 1/2(u 1 + u 2 ) and the dimensionless time ast = ut/b. For a Newtonian fluid s = 1, and s is defined by a non-linear function of a non-Newtonian fluid [76]. The film thickness equation has the form…”

Section: Calculation Of Friction Coefficient Using An Ehl Modelmentioning

confidence: 99%

“…where h 0 is the reference film thickness, d(X ,t) the total elastic deformation, S(X ,t) the composite surface roughness profile, and R the combined radius of curvature of the contact. A two-slope viscositypressure-temperature model [76] is used here as…”

Section: Calculation Of Friction Coefficient Using An Ehl Modelmentioning

confidence: 99%

“…P t is the transitional pressure, a threshold value beyond which an increase in viscosity changes its slope from α 1 to α 2 . Transition pressure values of P a = 0.7P t and P b = 1.4P t are used with P b = 380 MPa, a representative value for mineral oils [76].…”

Section: Calculation Of Friction Coefficient Using An Ehl Modelmentioning

confidence: 99%

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Prediction of friction-related power losses of hypoid gear pairs

Kahraman

2007

Proceedings of the Institution of Mechanical Engineers, Part K:

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A model to predict friction-related mechanical efficiency losses of hypoid gear pairs is proposed in this study. The model includes a gear contact model, a friction prediction model, and a mechanical efficiency formulation. The friction model uses a friction coefficient formula obtained by applying multiple linear regression analysis to a large number of elastohydrodynamic lubrication analyses covering typical ranges of key parameters associated with surface roughness, geometry, load, kinematics, and the lubricant. Formulations regarding the kinematic and geometric properties of the hypoid gear contact are presented. The load and friction coefficient distribution predictions are used to compute instantaneous torque/power losses and the mechanical efficiency of a hypoid gear pair at any given position. Results of a parametric study are presented at the end to highlight the influence of key operating conditions, surface finish, and lubricant properties on mechanical efficiency losses of hypoid gears.

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Section: Calculation Of Friction Coefficient Using An Ehl Modelmentioning

confidence: 99%

Section: Calculation Of Friction Coefficient Using An Ehl Modelmentioning

confidence: 99%

Section: Calculation Of Friction Coefficient Using An Ehl Modelmentioning

confidence: 99%

Section: Calculation Of Friction Coefficient Using An Ehl Modelmentioning

confidence: 99%

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Prediction of friction-related power losses of hypoid gear pairs

Kahraman

2007

Proceedings of the Institution of Mechanical Engineers, Part K:

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“…occurring in an asperity contact can be very high for heavy loads and high rolling speeds [6,7]. This pressure often ranges from 1.0 to 5.0 GPa on modern power transmission gears or roller bearings [8]. It will inevitably cause the elastoplastic or even fully plastic deformation in an asperity contact.…”

Section: Introductionmentioning

confidence: 99%

A Simplified Model for Calculating Hydrodynamic Lubrication Film Thickness in Elastoplastic Line Contacts

Zhang

2011

Flow Turbulence Combust

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The present paper proposes a simplified model for calculating hydrodynamic lubrication film thickness in elastoplastic line contacts. According to the SaintVenant's principle, the pressure in the contact is taken as uniformly distributed, this gives the contact surface elastic deformations in the inlet zone far away from the contact center close to real ones while gives those close to the contact center greater than real ones. This treatment is validated for hydrodynamic lubricated elastic contacts for relatively light loads and high rolling speeds. It gives the film thickness at the contact center a little higher than that calculated based on the real elastic model. The treatment is extended to a hydrodynamic lubricated elastoplastic line contact. The contact surfaces in the inlet zone are assumed as elastic and their deformations are calculated based on the uniform pressure distribution in the elastoplastic contact area. An inlet zone analysis is taken for obtaining the calculating equation of the hydrodynamic film thickness at the contact center. The equation overestimates the central film thickness but gives a satisfactory film thickness prediction for the heavy load which gives significant plastic deformations in the elastoplastic contact. It is found that when the load is lighter than 0.6 w pc , the contact can be taken as elastic when calculating the central film thickness, while when the load is heavier than 0.6 w pc , the contact can be taken as fully plastic; Here w pc is the critical load for the contact fully plastic deformation. The plastic deformation in an elastoplastic line contact is found to reduce the hydrodynamic lubrication film thickness in the contact. This reduction is greater for higher rolling speeds and heavier loads. However, it is significantly dropped with increasing surface hardness.

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Influence of Confriction on Intertooth Space Meshing Efficiency of Helical Gear in EHL

Wen-hong

Cui

2013

Proceedings of 20th International Conference on Industrial Engineering and Engineering Management

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A Deterministic Elastohydrodynamic Lubrication Model of High-Speed Rotorcraft Transmission Components

Cited by 26 publications

References 11 publications

Prediction of friction-related power losses of hypoid gear pairs

Prediction of friction-related power losses of hypoid gear pairs

A Simplified Model for Calculating Hydrodynamic Lubrication Film Thickness in Elastoplastic Line Contacts

Influence of Confriction on Intertooth Space Meshing Efficiency of Helical Gear in EHL

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